Disconnecting the battery will not resolve, though it may cancel your radio presets.
Steve is on the right track from my experience...
Here is what I have done:
On then off with the key 3 times, depress the brake pedal, followed by On then Off with the key 3 times ending in the On position (NOT RUN). This took several tries for me to get the sequence down right.
Your dash menu should display a message "reset LF Tire" or something similar. You then have 30 seconds to go out and place either a magnet or the proper tire reset tool near the tpms (sensor).
The horn will beep once if successful, then you can go over and do RF tire, then RR, then LR. If the reset fails (trying the magnet trick), the horn will beep twice. You would then have to start the key process all over.
A guy on the Explorer forum had listed the steps that I followed though while the dash display prompt and horn beeps I can attest to, I did not have luck using a magnet (though some have).
Some larger tire store chains may have the proper reset tool and be a little cheaper than the dealer.
There are reset tools I found on the Internet and eBay but they get a little pricey ($84 to $179+) unless you want to charge your friends to re-coop the cost.
Tool brands I found:
Bartec Wheelrite Tool - 300, 300+, 400+ models
OTC TIPS TPM Reset Tool OTC003D
www.fordtpms.com has a chart up to 2008 that I saw indicating what ford models have band strap tpms or schrader valve tpms. If you have a band strap tpms and its installed properly it should be located 180 degrees opposite the valve stem.
Hope this helps a little. My sensor failure is sporadic. Until it annoys me enough to go to a local tire store that has the right reset tool, I check tire pressure once a week and am living with the beep and dash message for now.
Good luck.